The present invention relates generally to wireless communications, and more particularly to reducing interference associated with wireless communications.
Wireless communication has been an active area of technology development. One wireless technology is wireless local area network (WLAN) systems, exemplified by the IEEE 802.11 and HiperLAN standards, also called wireless fidelity, or “Wi-Fi”, networks. In particular, Wi-Fi networks have gained acceptance in many businesses, agencies, schools, and homes as an alternative to a wired local area network. Further, many airports, hotels, cafes, and other facilities now offer public access to Wi-Fi networks (i.e., hot spots).
Wi-Fi networks are typically composed of access points. A conventional access point is a station that transmits and receives data and connects users to other users within the network. An access point can also serve as the point of interconnection between the wireless network and a fixed wire network. To improve the quality of wireless communications (e.g., to improve the reception of a mobile wireless device attempting to connect to the Wi-Fi network) and to maximize the coverage associated with an access point, access points are typically engineered to output the highest possible transmission power level within allowable limits.
Similarly, mobile wireless devices typically utilize whatever power is necessary within the allowable maximum to provide the highest quality of communications with an access point. As the mobile wireless device moves further away from an access point, and, consequently, as the signal strength received by the mobile wireless device from the access point decreases, the mobile wireless device traditionally increases its output transmission power to maintain the communications with the access point.
In some environments, there is highly sensitive electronic equipment that may be sensitive to electromagnetic interference. If the electronic equipment experiences interference, the electronic equipment may malfunction or halt its operation, with possible detrimental effects. For example, if a piece of electronic equipment in a hospital is monitoring a patient's vital signs, incorrect readings can result in a misdiagnosis. Similarly, if electronic equipment in a telecommunications equipment building experiences electromagnetic interference, the interference may result in an alarm and the equipment may shut down. The failure of such equipment may have a detrimental and costly effect. For example, the failure or malfunctioning of telecommunications equipment may impact service provided to thousands of customers.
Nonetheless, enabling use of wireless devices in these environments can provide many benefits. For example, enabling people to operate a handheld device without being restricted to a wired machine can provide substantial cost savings and significant service improvements. For example, in a central office (CO) of a telecommunications equipment building, technicians may have to walk to a particular terminal to determine the jobs that they have to work on. This terminal may be, for example, on the first floor of a CO. The location of the job, however, may be on the third floor of the CO. At some later time, the technician walks back to the terminal to enter the status of each job worked on thus far. Thus, the technician often has to walk to and from the terminal several times each day in order to update the job status for each job. These frequent walks to and from the terminal waste the technician's time. The telecommunications provider may consequently lose money because of the time delay between when the technician actually finishes the job and when the technician updates the job status on the terminal. Up to date job status, such as whether the job is completed or whether the hospital bed is ready, therefore, is often extremely relevant to reduce rework and to more efficiently use resources. Up-to-date job status can also be made available to customers for better customer service.
A technician carrying a wireless device, however, can update the job status in real-time once the technician has completed the job. The wireless device can then transmit the updated status to the terminal. Moreover, the technician does not have to walk back and forth between the job location and the terminal. Further, jobs can be transmitted to the technicians without having the technician walk back to the terminal. This is especially beneficial if inaccurate completion times create parity issues between competitors that share common carrier equipment. Parity violations due to inaccurate completion methods may lead to fines and penalties.
People carrying a wireless device in other buildings housing sensitive equipment experience similar benefits. For example, a doctor carrying a wireless device in a hospital can update the status of a patient immediately after examining the patient without walking back to a central area (e.g., the main desk) or computer (e.g., at the doctor's desk). Thus, a receptionist can begin processing the patient's information as soon as the doctor transmits the information via the doctor's wireless device. Similarly, a scientist in a nuclear power plant or in a research laboratory can, for example, wirelessly communicate results to other scientists without being limited to a central computer (or computers tethered to wired networks). These advantages, however, may not be realized in these buildings due to interference problems.
One solution to prevent interference to important, sensitive electronic equipment often greatly restrains individuals working around the equipment. In particular, building management typically does not allow any device that may generate interference to be taken into the building because of the cost and effect on service associated with interference. Thus, wireless devices such as pagers, cellular telephones, laptops, and personal digital assistants (PDAs) are not allowed in these buildings, thus keeping the building immune from interference.
Another solution to the problem associated with interference is to notify people (e.g., with signs or announcements) to shut off their wireless devices before they enter a room containing sensitive equipment or not to get within a particular distance of any piece of equipment. This solution is often ineffective, as people forget to follow (or ignore) the rule and cause interference.
Companies have also found that different pieces of sensitive equipment have different vulnerabilities to different frequencies and power levels of RF emissions. In other words, one particular frequency range and power level range may introduce more problems to one piece of sensitive equipment relative to another piece of sensitive equipment. To test every possible frequency and power level across all potential equipment, however, is an extremely burdensome and impractical task. Further, it may be impossible to find a frequency and power range that does not interfere with any equipment in a building.
Thus, there remains a need to reduce the interference associated with wireless devices in areas having sensitive electronic equipment in order to provide wireless capability to these areas and to accomplish that in an automated way to decrease the possibility of human error.